Final answer:
When the prefix 'en-' is added to 'rapture,' it becomes 'enrapture,' which is a verb meaning 'to cause great happiness.'
Step-by-step explanation:
The word rapture means "a feeling of extreme happiness." When the prefix en- is added to the word rapture, the word changes into enrapture. The correct answer for how the word changes is: (C) The part of speech changes from a noun to a verb and the meaning becomes "to cause great happiness." So when you enrapture someone, you are filling them with joy or delight.